Monocyte chemoattractant protein-1 and osteopontin differentially regulate monocytes recruitment in experimental glomerulonephritis

BACKGROUND

This study evaluated the mechanisms of monocyte/macrophage (M/M) infiltration in a rat model of anti-glomerular basement membrane glomerulonephritis (GN). We focused on chemokines and osteopontin, which are known regulators of M/M recruitment.

METHODS

Using immunohistology, in situ hybridization, and Northern blotting, the expression levels of chemokines and osteopontin were evaluated in isolated glomeruli and tubules 4, 10, and 20 days after the induction of GN. In vivo blocking experiments were performed by application of neutralizing antibodies against osteopontin and monocyte chemoattractant protein-1 (MCP-1).

RESULTS

In nephritic animals, high glomerular MCP-1 and RANTES (regulated upon activation normal T cell expressed and secreted) expression levels were observed on days 4 and 10. The tubular expression of MCP-1, however, was only slightly enhanced. In contrast, tubular osteopontin production was maximally stimulated (day 10) and paralleled with peaks of albuminuria and tubulointerstitial M/M infiltration. Application of an anti-osteopontin antibody ameliorated tubulointerstitial and glomerular M/M recruitment, whereas treatment with an anti-MCP-1 antibody selectively reduced glomerular M/M recruitment. However, tubulointerstitial M/M infiltration remained unchanged.

CONCLUSION

These studies show that chemokines and osteopontin are differentially expressed in glomeruli and tubules in this model of GN. Chemokines play a primary role in the glomeruli, whereas osteopontin has a predominant role in tubulointerstitial M/M recruitment. The roles of chemokines and osteopontin may thus be dependent on the renal compartment and on the disease model.

Intestinal proliferation and delayed intestinal transit in a patient with a GLP-1-, GLP-2- and PYY-producing neuroendocrine carcinoma

Glucagon-like peptides (GLP) 1 and 2 are hormones derived from the post-translational processing of proglucagon in the intestinal L cells that influence intestinal motility and small bowel growth, respectively. We describe a patient with a neuroendocrine tumor of unknown primary origin with peritoneal carcinomatosis and diffuse liver metastases, who presented with constipation and nocturnal itching for over 3 years. Small bowel follow-through showed decreased small intestinal motility and marked intestinal hypertrophy. Biopsies from mesenterial lymph nodes showed, histologically, a well-differentiated neuroendocrine tumor (G1), with positive immunostaining for chromogranin A, GLP-1, GLP-2 and polypeptide YY (PYY). Jejunal biopsy demonstrated marked intestinal mucosal hypertrophy. HPLC analysis combined with RIA of tumor and serum extracts revealed that the tumor was producing and releasing fasting levels of GLP-1 of 738+/-20.7 pg/ml (normal levels (nl) <100 pg/ml), GLP-2 of 3,150+/-9 pg/ml (nl <100 pg/ml) as well as PYY 550 pg/ml (nl <100 pg/ml). Octreotide administration decreased levels of GLP-1 and GLP-2 and reduced small intestinal transit time from 150 to 50 min. However, tumor growth was not inhibited by octreotide, interferon or dacarbazine therapy and the patient died 8 months later. This is the first case report demonstrating the overproduction of GLP-1, GLP-2 and PYY from an neuroendocrine tumor, in a patient with intestinal hypertrophy and delayed intestinal transit time.

h-sgk serine-threonine protein kinase as transcriptional target of p38/MAP kinase pathway in HepG2 human hepatoma cells

The human serum and glucocorticoid dependent serine/threonine kinase h-sgk has previously been discovered as cell volume regulated gene. The present study has been performed to elucidate the involvement of p38-kinase in the transcriptional control of h-sgk by osmotic cell shrinkage. The p38-kinase has previously been cloned as the mammalian homologue of HOG1 kinase, which constitutes a part of the osmosensor in the yeast Saccharomyces cerevisiae. Phosphorylated (active) p38-kinase has been estimated with Western blotting, transcription of hsgk using Northern blotting. Both, increase of extracellular NaCl concentration by 50 mmol/l and addition of 10 micromol/l anisomycin increase phosphorylation of the p38-kinase within 5 to 10 minutes. h-sgk transcription is upregulated by addition of 50 mmol/l NaCl and by anisomycin (10 micromol/l), effects completely inhibited by the specific p38-kinase inhibitor, SB 203580 (10 micromol/l). In conclusion, the stimulation of h-sgk transcription by osmotic cell shrinkage is mediated by p38-kinase.

Aldose and aldehyde reductases: correlation of molecular modeling and mass spectrometric studies on the binding of inhibitors to the active site

Aldose and aldehyde reductases are monomeric NADPH-dependent oxidoreductases that catalyze the reduction of a wide variety of aldehydes and ketones to their corresponding alcohols. The overall three-dimensional structures of the enzymes are composed of similar alpha/beta TIM-barrels, and the active site residues Tyr 50, His 113, and Trp 114 interacting with the hydrophilic heads of inhibitors are conserved. We have used molecular modeling and mass spectrometry to characterize the interactions between the enzymes and three aldose reductase inhibitors: tolrestat, sorbinil, and zopolrestat. Unlike the IC(50) values (concentration of inhibitor giving 50% of inhibition in solution), the Vc(50) values measured by mass spectrometry (accelerating voltage of ions needed to dissociate 50% of a noncovalent complex in the gas phase) for the two enzymes are similar, and they correlate with the electrostatic and hydrogen-bonding energies calculated between the conserved Tyr 50, His 113, and Trp 114 and the inhibitors. The results of our comparison agree with detailed structural information obtained by X-ray crystallography, suggesting that nonconserved residues from the C-terminal loop account for differences in IC(50) values for the two enzymes. Additionally, they confirm our previous assumption that the Vc(50) values reflect the enzyme-inhibitor electrostatic and hydrogen-bonding interactions and exclude the hydrophobic interactions.

Parathyroid xenotransplantation without immunosuppression in experimental hypoparathyroidism: long-term in vivo function following microencapsulation with a clinically suitable alginate

Permanent hypoparathyroidism is one of the most difficult of all endocrine disorders to treat medically. Because this deficiency syndrome rarely is a life-threatening condition, systemic immunosuppression for recipients of transgenic transplants is not justified. An alternative would be protecting the tissue to be transplanted from the immunologic response (immunoisolation) by coating it with a semipermeable membrane- microencapsulation. Unfortunately, prior to the first clinical use, further analysis of the coating substance (alginate) demonstrated that it has potential cancerogenic properties. Using a purified amitogenic alginate suitable for clinical use, we accomplished allotransplantation in a long-term animal model and reported the first clinical cases without postoperative immunosuppression recently. In view of the potential clinical use, we investigated the ability of the microencapsulation technology with the novel amitogenic alginate in experimental hypoparathyroidism (80 parathyroidectomized rats) to enable transgenic transplantation across the highest immunologic barrier (xenotransplantation: human to rat) to ensure intact transplant function without immunosuppression. In a controlled, long-term animal study, the effect of microencapsulation on xenotransplanted human parathyroid tissue was evaluated over a period of 30 weeks (microencapsulated and naked hyperplastic parathyroid tissue, respectively). Functionally, human parathyroid tissue was able to replace that of rats. More than 6 months after xenotransplantation 32 of 40 animals that had received microencapsulated transplants were normocalcemic. In contrast, serum calcium concentrations dropped to postparathyroidectomy levels within 3 weeks in the animals that had received naked tissue only. Correspondingly, normocalcemic animals showed vital parathyroid tissue inside the microcapsules, which were surrounded by a small rim of fibroblasts. When combining microencapsulation with an improved tissue culture method, xenotransplantation of human parathyroid tissue and maintenance of its physiologic function is reproducibly achieved over the highest transplantation barrier. Using the amitogenic alginate may be a crucial step toward the first clinical use of this technique for parathyroid xenotransplantation without immunosuppression.

A RET double mutation in the germline of a kindred with FMTC

Activating germline mutations of the RET proto-oncogene are found in more than 90% of families with multiple endocrine neoplasia type 2a (MEN 2a) and familial medullary thyroid carcinoma (FMTC). The majority of patients with these hereditary tumors carry germline mutations that result in the substitution of one of five cysteine residues in exon 10 and 11. Different mutations in exons 13, 14 and 15 affecting non-cysteine residues have also been described but are considered to be rare. We now for the first time report a double mutation of the RET proto-oncogene occurring in the germline of a kindred with FMTC. Both mutations occur within the tyrosine kinase domain in exon 14 and lead to the substitution of valine 804 by methionine and arginine 844 by leucine. Since the double mutated allele cosegregated with the disease and was not identified in 200 unrelated normal probands, we conclude that they represent mutations that predispose the individual to the development of FMTC with a mild phenotype.

Aicardi-Goutières syndrome displays genetic heterogeneity with one locus (AGS1) on chromosome 3p21

We have studied 23 children from 13 families with a clinical diagnosis of Aicardi-Goutières syndrome. Affected individuals had developed an early-onset progressive encephalopathy that was characterized by a normal head circumference at birth, basal ganglia calcification, negative viral studies, and abnormalities of cerebrospinal fluid comprising either raised white cell counts and/or raised levels of interferon-alpha. By means of genomewide linkage analysis, a maximum-heterogeneity LOD score of 5.28 was reached at marker D3S3563, with alpha=.48, where alpha is the proportion of families showing linkage. Our data suggest the existence of locus heterogeneity in Aicardi-Goutières syndrome and highlight potential difficulties in the differentiation of this condition from pseudo-TORCH (toxoplasmosis, rubella, cytomegalovirus, and herpes simplex virus types 1 and 2) syndrome.

Are covered stents really effective at closing esophagotracheal fistulas? Results of an animal study

PURPOSE

To determine whether covered self-expanding metal stents successfully exclude experimentally created esophagotracheal fistulas.

METHODS

Esophagotracheal fistulas were surgically created in the upper third of the esophagus in 12 minipigs and immediately sealed by implantation of a covered self-expanding metal stent (20 mm expanded diameter) in the esophagus. Before the animals were killed, after 3, 7, 14, 28, 30, and 36 days, the position of the stent and the sealing of the fistula were monitored fluoroscopically. The esophagus, trachea, and both lungs were examined histologically.

RESULTS

Creation of an esophagotracheal fistula was successful in all cases. All fistulas were widely patent at autopsy. The technical success rate for stent deployment and initial sealing of the fistula was 100%. During follow-up, five stents migrated distally, but none into the stomach. Therefore, the fistula was no longer excluded in five animals. In seven animals the stent sealed the fistula until the death of the animal. Tracheal narrowing necessitated additional tracheal stenting in three animals. Two minipigs died due to aspiration of food. Histologic examination showed signs of aspiration in all animals with stents in place for longer than 2 weeks.

CONCLUSION

This experimental animal study revealed worse results for sealing of esophagotracheal fistulas with covered self-expanding metal stents than have been reported for the clinical use of these devices.

The structure of human aldose reductase bound to the inhibitor IDD384

The crystallographic structure of the complex between human aldose reductase (AR2) and one of its inhibitors, IDD384, has been solved at 1.7 A resolution from crystals obtained at pH 5.0. This structure shows that the binding of the inhibitor's hydrophilic head to the catalytic residues Tyr48 and His110 differs from that found previously with porcine AR2. The difference is attributed to a change in the protonation state of the inhibitor (pK(a) = 4.52) when soaked with crystals of human (at pH 5.0) or pig lens AR2 (at pH 6.2). This work demonstrates how strongly the detailed binding of the inhibitor's polar head depends on its protonation state.

Essential role of a single arginine of photosystem I in stabilizing the electron transfer complex with ferredoxin

PsaE is one of the photosystem I subunits involved in ferredoxin binding. The central role of arginine 39 of this 8-kDa peripheral polypeptide has been established by a series of mutations. The neutral substitution R39Q leads to a 250-fold increase of the dissociation constant K(d) of the photosystem I-ferredoxin complex, as large as the increase induced by PsaE deletion. At pH 8.0, this K(d) value strongly depends on the charge of the residue substituting Arg-39: 0.22 microM for wild type, 1.5 microM for R39K, 56 microM for R39Q, and more than 100 microM for R39D. The consequences of arginine 39 substitution for the titratable histidine were analyzed as a function of pH. The K(d) value of R39H is increased 140 times at pH 8.0 but only 5 times at pH 5.8, which is assigned to the protonation of histidine at low pH. In the mutant R39Q, the association rate of ferredoxin was decreased 3-fold compared with wild type, whereas an 80-fold increase is calculated for the dissociation rate. We propose that a major contribution of PsaE is to provide a prominent positive charge at position 39 for controlling the electrostatic interaction and lifetime of the complex with ferredoxin.

Subchondral magnetic resonance imaging changes in early osteoarthrosis associated with tibial osteonecrosis

SUMMARY

The authors report on 41 patients with acute or subacute knee pain and early or midstage degenerative arthrosis with osteonecrotic lesions in the subchondral and metaphyseal region of the medial proximal tibia. Each lesion was identified only on magnetic resonance images (MRI). These MRI changes are classified and the clinical course is defined during a follow-up period averaging 4.5 years. Radiographically, 22 patients had minimal degenerative changes; 12 had moderate arthritis; and 7 were normal. With MRI, 3 distinct types of lesions were identified. Type A lesions had localized areas of decreased signal in the subchondral area. Type B lesions had diffuse signal changes with extension into the metaphysis. Type C lesions had metaphyseal involvement as well as a marginated serpentine subchondral rim usually associated with advanced osteonecrosis. There were 9 type A lesions, 23 type B, and 9 type C. At the end of 1 year, 33 patients (80%) had no or mild symptoms, and 8 (20%) had persistent moderate pain. At 4.5-year follow-up, most patients had symptoms consistent with progressive osteoarthrosis, 12 patients had severe symptoms (29%), 17 (41%) had mild or moderate symptoms, and only 12 (29%) were asymptomatic or had minimal symptoms. The type of MRI change seen initially was predictive of prognosis. Only 6 (19%) of the 32 patients with type A or B findings had severe symptoms at last follow-up. Six (66%) of the 9 patients with a type C MRI lesion had severe symptoms or had an operation by last follow-up. Twelve patients had follow-up MRI at a mean 15 months (range, 12 to 18 months) after the initial evaluation. The type A and B changes were either absent or significantly reduced. The type C subchondral marginated rim changes remained but metaphyseal involvement was reduced. There appears to be a spectrum of tibial subchondral MRI changes associated with sudden onset of medial knee pain in patients with early osteoarthritis of the knee. These changes may be indicative of osteonecrosis. The initial MRI classification is useful in predicting prognosis. Recognition of this problem may avoid unnecessary intra-articular surgery.

Total knee arthroplasty in patients 90 years of age and older

With increasing longevity, more patients older than age 90 now are becoming candidates for total knee arthroplasty. This article reviews our experience with the perioperative morbidity and early outcomes in 12 patients older than age 90, undergoing 15 total knee surgeries. Postoperative Knee Society clinical and functional scores showed excellent outcomes, and the quality of life is enhanced. There were no significant surgical complications; however, there were several nonsurgical complications, including mental confusion (3), urinary retention (3), atrial fibrillation (2), atrial flutter (1), and gallstone retention and gastrointestinal bleed (1). Most of these complications stemmed directly from the preoperative medical condition. These are predictive and therefore may be recognized early and treated aggressively. Total knee surgery can be performed safely in patients older than 90 years old with excellent pain relief and enhanced quality of life. The surgeon should be aware of the patient's past medical history because this predisposes to postoperative morbidity.

Predonated autologous blood transfusions after total knee arthroplasty: immediate versus delayed administration

Efforts to avoid complications associated with transfusion of allogeneic blood have increased the use of preoperatively donated autologous blood (PAB). A major controversy has arisen: Should the same criteria be used for transfusion of autologous as allogeneic red cells? This study prospectively and randomly compared giving PAB immediately after total knee arthroplasty (TKA), beginning in the recovery room or delaying a transfusion until the patient's hemoglobin had fallen to less than a 9.0 g/dL transfusion trigger point. The results show that patients who received immediate transfusion had fewer nonsurgical complications (P < .002). Because TKAs are associated with an average blood loss of 1,400 mL, we recommend that PAB be used in the immediate postoperative period, especially in the elderly, in whom the risk for cardiac or nonsurgical complications is inherently increased.

Binding of aldose reductase inhibitors: correlation of crystallographic and mass spectrometric studies

Aldose reductase is a NADP(H)-dependent enzyme, believed to be strongly implicated in the development of degenerative complications of Diabetes Mellitus. The search for specific inhibitors of this enzyme has thus become a major pharmaceutic challenge. In this study, we applied both X-ray crystallography and mass spectrometry to characterize the interactions between aldose reductase and four representative inhibitors: AminoSNM, Imirestat, LCB3071, and IDD384. If crystallography remains obviously the only way to get an extensive description of the contacts between an inhibitor and the enzymatic site, the duration of the crystallographic analysis makes this technique incompatible with high throughput screenings of inhibitors. On the other hand, dissociation experiments monitored by mass spectrometry permitted us to evaluate rapidly the relative gas-phase stabilities of the aldose reductase-inhibitor noncovalent complexes. In our experiments, dissociation in the gas-phase was provoked by increasing the accelerating voltage of the ions (Vc) in the source-analyzer interface region: the Vc value needed to dissociate 50% of the noncovalent complex initially present (Vc50) was taken as a gas-phase stability parameter of the enzyme-inhibitor complex. Interestingly, the Vc50 were found to correlate with the energy of the electrostatic and H-bond interactions involved in the contact aldose reductase/inhibitor (Eel-H), computed from the crystallographic model. This finding may be specially interesting in a context of drug development. Actually, during a drug design optimization phase, the binding of the drug to the target enzyme is often optimized by modifying its interatomic electrostatic and H-bond contacts; because they usually depend on a single atom change on the drug, and are easier to introduce than the hydrophobic interactions. Therefore, the Vc50 may help to monitor the chemical modifications introduced in new inhibitors. X-ray crystallography is clearly needed to get the details of the contacts and to rationalize the design. Nevertheless, once the cycle of chemical modification is engaged, mass spectrometry can be used to select a priori the drug candidates which are worthy of further crystallographic investigation. We thus propose to use the two techniques in a complementary way, to improve the screening of large collections of inhibitors.

Higher frequency of DPC4/Smad4 alterations in pancreatic cancer cell lines than in primary pancreatic adenocarcinomas

The tumor suppressor gene DPC4/Smad4 at 18q21.1 is inactive in about 50% of pancreatic carcinoma xenografts and cell lines. However, the role of DPC4 in the multistep carcinogenesis of primary pancreatic adenocarcinomas remains uncertain. Therefore, we examined 45 primary human pancreatic adenocarcinomas and 12 pancreatic cancer cell lines for DPC4 alterations by single-strand conformational variant (SSCV) analysis and a PCR-based deletion assay. DPC4 was inactivated by either homozygous deletion or point mutation in 6 of 12 cell lines (50%). None of the primary pancreatic carcinomas carried a DPC4 mutation, although 66% revealed LOH of 18q21 sequences. These findings suggest that inactivation of DPC4 occurs more frequently in tumor-derived cell lines than in primary pancreatic adenocarcinomas. In addition, another, yet unidentified, tumor suppressor gene(s) may be linked with the frequent LOH of 18q21 in primary pancreatic adenocarcinomas.

h-sgk serine-threonine protein kinase gene as transcriptional target of transforming growth factor beta in human intestine

BACKGROUND & AIMS

Recently, the immediate early gene h-sgk was cloned as a hypertonicity-induced gene from human hepatoma cells. The aim of this study was to localize h-sgk messenger RNA (mRNA) expression in normal and inflamed intestinal mucosa and to identify potential transcriptional regulators.

METHODS

h-sgk mRNA in small intestinal mucosa from healthy persons and patients with Crohn's disease was determined by in situ hybridization. Transcriptional regulation was studied by Northern blot analysis of total RNA isolated from cultured human Intestine 407, U937, and HepG2 cells.

RESULTS

In normal ileum, h-sgk mRNA was selectively localized to the apical villus enterocytes, whereas no staining was detected in crypt cells. In Crohn's disease, enterocytes of the crypts expressed h-sgk and abundant h-sgk positive inflammatory cells appeared in the lamina propria. Combined h-sgk in situ hybridization and immunohistochemical analysis of CD68 antigen expression identified a part of these cells as macrophages. In addition to spatial correlation of transforming growth factor (TGF)-beta1 protein and h-sgk mRNA expression, h-sgk transcription in human Intestine 407 and HepG2 cells as well as in U937 monocytes/macrophages was strongly induced by TGF-beta1 in vitro.

CONCLUSIONS

h-sgk expression in normal and inflamed intestinal mucosa may be regulated by TGF-beta1 and may contribute to the pleiotropic actions of TGF-beta1 in mucosal cell populations.

Mutations of the DPC4/Smad4 gene in neuroendocrine pancreatic tumors

Tumors of the endocrine pancreas are extremely rare, and molecular mechanisms leading to their development are not well understood. A candidate tumor suppressor gene, DPC4, located at 18q21, has recently been shown to be inactivated in half of pancreatic adenocarcinoma xenografts. The close anatomical relationship of the exocrine and endocrine pancreas prompted us to determine the role of DPC4 in the tumorigenesis of 25 pancreatic islet cell tumors (11 insulinomas, nine non-functioning endocrine carcinomas, three gastrinomas, two vipomas). A mutation screening of the highly conserved COOH-terminal domain of DPC4 (exons 8-11) was performed by single-strand conformational variant (SSCP) analysis and a PCR-based deletion assay. Five of nine (55%) non-functioning endocrine pancreatic carcinomas revealed either point mutations, small intragenic deletions or homozygous deletion of DPC4 sequences compared to none of the insulinomas, gastrinomas or vipomas. These results suggest that DPC4 is an important target gene promoting tumorigenesis of non-functioning neuroendocrine pancreatic carcinomas.

[Pulmonary, nodular cavernous, calcifying form of amyloidosis]

We report a rare case of pulmonary nodular amyloidosis featuring all typical morphologic alterations associated with this disease; multiple amyloidomas, calcification and cavernous transformation were present. Definite diagnosis was established histologically with CT-guided biopsy. The different types of pulmonary amyloidosis and their radiological appearances are described and discussed.

Production of crystals of human aldose reductase with very high resolution diffraction

As the action of human aldose reductase (hAR) is thought to be linked to the pathogenesis of diabetic complications, much effort has been directed towards the analysis of the catalytic mechanism and the development of specific inhibitors. Here, the crystallization of recombinant hAR with its cofactor NADP+ at 277 K in the presence of the precipitating agent PEG 6000 is reported. The crystals diffract to high resolution (1.1 A) and belong to the P21 space group with unit-cell parameters a = 49.97, b = 67.14, c = 48. 02 A, beta = 92.2 degrees with one molecule per asymmetric unit. Seleno-substituted hAR crystals were also produced and diffract to 1. 7 A on a conventional X-ray source.

Molecular and functional characterization of s-KCNQ1 potassium channel from rectal gland of Squalus acanthias

Functional and pharmacological data point to the involvement of KCNQ1/IsK potassium channels in the basolateral potassium conductance of secretory epithelia. In this study, we report the cloning and electrophysiological characterization of the KCNQ1 protein from the salt secretory rectal gland of the spiny dogfish (Squalus acanthias). The S. acanthias KCNQ1 (s-KCNQ1) cDNA was cloned by polymerase chain reaction (PCR) intensive techniques and showed overall sequence similarities with the KCNQ1 potassium channel subunits of Man, mouse and Xenopus laevis of 64, 70 and 77%, respectively, at the translated amino acid level. Analysis of s-KCNQ1 expression on a Northern blot containing RNA from heart, rectal gland, kidney, brain, intestine, testis, liver and gills revealed distinct expression of 7.4-kb s-KCNQ1 transcripts only in rectal gland and heart. Voltage-clamp analysis of s-KCNQ1 expressed in Xenopus oocytes showed pronounced electrophysiological similarities to human and murine KCNQ1 isoforms, with a comparable sensitivity to inhibition by the chromanol 293B. Coexpression of s-KCNQ1 with human-IsK (h-IsK) induced currents with faster activation kinetics and stronger rectification than observed after coexpression of human KCNQ1 with h-IsK, with the voltage threshold of activation shifted to more negative potentials. The low activation threshold at approximately -60 mV in combination with the high expression in rectal gland cells make s-KCNQ1 a potential candidate responsible for the basolateral potassium conductance.

Total knee arthroplasty in morbidly obese patients

We reviewed the clinical outcomes of fifty primary total knee arthroplasties that had been performed with cement in forty patients who were considered morbidly obese (a Quetelet index of more than forty). These results were compared with those of 1768 similar procedures, performed during the same time-period by the same surgeon, in 1539 patients who were not morbidly obese (controls). At a mean of approximately five years postoperatively, there was a significant difference between the morbidly obese patients and the control group with regard to the knee and functional scores (84 and 53 points compared with 92 and 67 points; p < 0.00005 for both scores). No significant difference was detected, with the numbers available, with regard to the range of motion or the radiographic score (p = 0.77). The rate of perioperative complications was significantly higher in the morbidly obese patients (p < 0.00005). Of the fifty knees in these patients, eleven (22 percent) had a wound complication, five (10 percent) had an infection, and four (8 percent) had an avulsion of the medial collateral ligament. The five infections developed within twenty weeks after the operation, and three were associated with a wound complication. In comparison, thirty-five (2 percent) of the 1768 knees in the control group had a wound complication, eleven (0.6 percent) had an infection, and none had an avulsion of the medial collateral ligament. We concluded that total knee arthroplasty in morbidly obese patients can be successful but is associated with an increased rate of perioperative complications, including problems with wound-healing, infection, and avulsion of the medial collateral ligament. Alterations in the operative technique for soft-tissue closure and protection of the medial collateral ligament have decreased the rates of complications related to wound-healing and the medial collateral ligament.